The Use of Breast-Conserving Surgery versus Mastectomies for Breast Cancer Resections

Key message

The use of breast-conserving surgery appears to have increased in six provinces from 2008/09–2010/11 to 2011/12–2013/14.

Indicator definition

The percentage of women receiving a breast cancer resection for whom breast-conserving surgery (BCS) was their final procedure (i.e., where BCS was their first surgery or where a wider excision in the context of BCS was performed within one year of their first surgery). The data include women with unilateral invasive breast cancer whose surgery occurred between April 2008 and March 2014. Results are presented by province and year.

Measured since

The 2012 Cancer System Performance Report.

Why measure this?

Most women diagnosed with non-metastatic breast cancer are candidates for surgery, either mastectomy or breast-conserving surgery^† followed by whole-breast radiation therapy (breast-conservation therapy).¹ Breast-conservation therapy is less invasive than mastectomy and is associated with lower morbidity, improved cosmetic appearance and better psychological outcomes. In addition, mastectomy and breast-conservation therapy yield comparable survival outcomes.^2-6 Since both procedures provide comparable outcomes, the choice between mastectomy and breast-conservation therapy should be made by the patient based on a clear understanding of the risks, benefits and quality of life considerations associated with each choice.

What are the key findings?

• The use of breast-conserving surgery ranged from 30.8% in Newfoundland and Labrador to 75.1% in Quebec (Figure 4.5).
• The use of breast-conserving surgery appears to have increased in six provinces (British Columbia, Alberta, Ontario, Quebec, New Brunswick and Nova Scotia) from 2008/09–2010/11 to 2011/12–2013/14^†† (Figure 4.6).

Notes

^† Mastectomy is surgery to remove the entire breast. Breast-conserving surgery involves complete removal of the tumour along with a margin of non-cancerous breast tissue.

^†† The period 2008–10 refers to April 2008 to March 2011. The period 2011–14 refers to April 2011 to March 2014.

Why do these findings matter?

Across Canada, the use of breast-conserving surgery as a final procedure has increased in six provinces. This finding could indicate that more women are receiving breast-conserving surgery. Mastectomy and breast-conserving surgery followed by radiation therapy yield comparable survival outcomes.^2-6 As such, the interprovincial differences shown here do not necessarily reflect differences in the quality of care. The choice between breast-conserving surgery followed by radiation therapy and mastectomy should be made by the patient based on a clear understanding of the benefits, risks and quality of life considerations associated with each treatment option.

There is evidence that distance from a radiation treatment centre influences breast-conserving surgery rates. Patients who live far from the nearest radiation treatment centre may be less likely to undergo breast-conserving surgery due to the challenges of travelling post-operatively to a radiation treatment facility for several weeks of treatment. The choice of treatment may also be influenced by access to breast reconstruction, clinical factors (e.g., gene mutations that may predispose a woman to develop breast cancer, which can influence women to choose prophylactic removal of one or both breasts), surgeon preferences and training, and patient preferences.

References

1. National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Breast Cancer Version 1.2016. 2015.
2. Darby S, McGale P, Correa C, Taylor C, Arriagada R, Clarke M, et al. Effect of radiotherapy after breast-conserving surgery on 10-year recurrence and 15-year breast cancer death: meta-analysis of individual patient data for 10,801 women in 17 randomised trials. Lancet. 2011 Nov 12;378(9804):1707-16.
3. Veronesi U, Cascinelli N, Mariani L, Greco M, Saccozzi R, Luini A, et al. Twenty-year follow-up of a randomized study comparing breast-conserving surgery with radical mastectomy for early breast cancer. N Engl J Med. 2002 Oct 17;347(16):1227-32.
4. Clarke M, Collins R, Darby S, Davies C, Elphinstone P, Evans V, et al. Effects of radiotherapy and of differences in the extent of surgery for early breast cancer on local recurrence and 15-year survival: an overview of the randomised trials. Lancet. 2005 Dec 17;366(9503):2087-106.
5. Arriagada R, Le MG, Rochard F, Contesso G. Conservative treatment versus mastectomy in early breast cancer: patterns of failure with 15 years of follow-up data. Institut Gustave-Roussy Breast Cancer Group. J Clin Oncol. 1996 May;14(5):1558-64.
6. Fisher B, Anderson S, Bryant J, Margolese RG, Deutsch M, Fisher ER, et al. Twenty-year follow-up of a randomized trial comparing total mastectomy, lumpectomy, and lumpectomy plus irradiation for the treatment of invasive breast cancer. N Engl J Med. 2002 Oct 17;347(16):1233-41.